Based on the context of your question, it seems like you are looking for the culture that assisted European settlement in North America. Given your options, it may be helpful to clarify what is meant by "helped."
- The Pilgrims are known for establishing one of the first successful colonies in North America (Plymouth), but they were European settlers themselves.
- The Iroquois were indeed a significant indigenous group in North America prior to European arrival, and they played a complex role in the interactions with Europeans, but they did not inherently "help" European settlement.
- The term explorer is too broad and generally refers to individuals like Columbus or John Cabot rather than a distinct culture.
- The Spanish were among the first Europeans to explore and settle parts of North America, particularly in the Southwest.
If the question is asking about cultures that directly aided European settlement, the Spanish would be the most appropriate choice as they were actively involved in establishing settlements and colonies.
Please review your question's context for specific wording, as "helped" might imply different interpretations.